奶牛乳腺炎诊断方法研究进展

奶牛乳腺炎的诊断方法有很多,临床乳腺炎可根据临床症状进行诊断,用于隐性乳腺炎的诊断方法有乳汁细胞学检查、乳汁的细菌培养、电导率测定、pH值的检查、乳清电泳诊断法、酶检测法、PCR检测方法、被毛微量元素检验法以及其它衍生方法.本文对奶牛乳房炎诊断研究进展作了系统的介绍.     

可发酵碳水化合物减少猪场臭气的机理和应用

可发酵碳水化合物,添加在猪日粮中到达后肠作为微生物发酵的底物,通过改变猪肠道和粪便中的微生物及其发酵过程,改变粪尿的理化特性,来减少氨的挥发以及臭气的产生.本文对臭气和除臭方法进行了简单的介绍,并综述了通过在猪日粮中添加可发酵碳水化合物来控制猪场臭气的机理和应用效果.     

铬对泌乳期奶牛的生产性能和主要生理指标的影响

研究了泌乳期奶牛日粮中添加吡啶羧酸铬或赖氨酸铬对其生产性能和血液主要生理指标的影响。选择75头泌乳前期（〈80d）的荷斯坦奶牛随机分为试验组A、B和对照组C。试验组A和B每天日粮中分别补充吡啶羧酸铬和赖氨酸铬，供试期间对照组C不添加有机铬。结果表明：铬可提高泌乳期奶牛的生产性能，增强和改善泌乳奶牛的免疫力和应激状态。试验组A和试验组B泌乳量高于对照组C（P〈0．01）；试验组B血清中的甘油三酯的浓度低于对照组C（P〈0．05）；试验组A血清中胰岛素浓度低于对照组C（P〈0．01）；试验组A和试验组B血清中葡萄糖浓度都高于对照组C（P〈0．01）；试验组A和试验组B血清中皮质醇的浓度分别比对照组C低7．21nmol／L和4．92nmol／L，试验组A和试验组B血清中IgG的浓度分别比对照组C高2．1g／L和3．1g／L。     

利用分离的奶牛X精子冷冻精液生产体内性控胚胎试验

采用常规精液和分离的X精子冷冻精液对115头超数排卵的青年和经产荷斯坦母牛人工输精生产体内性控胚胎。结果表明,利用2支和3支性控精液给超排青年母牛输精,头均分别获得6.8枚±4.8枚和6.3枚±3.2枚可用胚胎,与常规精液的超排效果(7.2枚±5.2枚)无明显差异;利用2支和3支性控精液给超排经产母牛输精,头均可用胚胎分别为7.5枚±4.5枚和8.6枚±5.6枚,与常规精液的超排效果(6.1枚±3.2枚)相比,分别增加23%(P>0.05)和41%(P>0.05),无显著差异,但解冻后性控精子会明显影响经产母牛的受精率;对用性控精液输精生产的12枚抽样胚胎采用LAMP法进行性别鉴定并移植,结果获得了91.7%的雌性率和36.4%的受胎率。结果提示,X精子的分离过程会在一定程度上影响受精率,用分离的X精子冷冻精液对超排母牛进行人工授精生产体内性控胚胎是可行的。     

PEF辅助快速提取非特异性奶牛脾脏转移因子的实验研究

应用PEF成功从奶牛脾脏中提取非特异性转移因子，并与常规提取法和复合酶提取法进行了比较.经理化特性分析，奶牛脾脏转移因子是以低分子多肽（〈10kD）为主的混合物，含有少量核酸和氨基酸.实验表明，将物料溶解于6倍质量的磷酸盐（pH7．0）缓；中液中，在脉冲电场强度为25kV／cm，脉冲数为16μs，和流速为2mL／min的条件下，提取液中低分子多肽的含量有最大值9．85mg／mL.PEF提取率是常规方法的2倍，复合酶法的1．47倍.PEF法耗时短，操作简单，成本低，因此，PEF提取是一种很有希望的提取非特异性奶牛脾脏转移因子方法.     

The management of intensive dairy farms can be improved for better welfare and milk yield

The intensive breeding is often considered a risk of low welfare in dairy cows. Namely, the high yield has been suggested to be per se a cause of well-being reduction. Conversely, we have in many farms demonstrated that high milk yielding cows are not necessarily in a bad welfare condition, while many environmental and management problems can cause a distress situation and a reduced milk yield. To confirm these results, in an average yielding dairy farm affected by several problems, the welfare was assessed according to an Integrated Diagnostic System which considers health status, milk yield and quality, feeding strategy, blood profiles etc. The same check-up has been repeated a year later, after some attempts to correct main mistakes previously observed: dry and lactating cow diets, n° of cubicles, hygiene conditions, preparation and milking procedures etc. In one year only part of the mistakes have been fully corrected; nevertheless, the animal response was definitively improved suggesting a better welfare situation: improvement of teat and body condition (BCS) scores and reduction of open days, of legs and feet lesions and of somatic cell count (SCC : 283 vs. 456 cells/μl) as well as an increase of milk yield (25.2 vs. 20.1 kg/d).

Results confirmed that better breeding techniques can optimise the animal welfare and optimise milk yield in the intensive systems.     

Influence of low phosphorus intake during early lactation on apparent digestibility of phosphorus and bone metabolism in dairy cows

In this study, the effects of reducing the dietary phosphorus (P) supply during the first 4 months of lactation on P balance and bone metabolism were investigated in dairy cows during a full lactation, including the dry period. Twenty-two multiparous cows of the Swedish Red and White Breed were included in the experiment. Eleven cows received a dietary P concentration of 0.43% of DM during the whole lactation (NP), and 11 cows received a dietary P concentration of 0.32% of DM during the first 4 months of lactation, followed by 0.43% of DM during the rest of lactation (LP). Total collection of faeces was carried out during five different stages of lactation, for 5 consecutive days at each occasion. The dynamics of bone metabolism was investigated by monitoring one bone-formation marker, identifying osteocalcin (OC), and one bone-resorption marker identifying C-telopeptide fragments of collagen type I (CTx) in blood plasma. At the two first collection periods, 3–7 and 11–15 weeks after parturition, the apparent digestibility of P was higher in the LP cows (52%) than in the NP cows (42%). During the following collection periods, no difference in the apparent digestibility could be noted between the two groups of cows. Phosphorus retention did not differ between treatments at any collection period. The highest retention was observed during late lactation and during the dry period. The profiles of the bone metabolism markers indicated a net resorption of bone during early lactation, but there were no differences in marker concentrations between the groups during early lactation, indicating that the LP diet did not induce a further elevated net bone resorption.     

不同处理稻草混合青贮料对奶牛生产性能的影响

本试验采用稻草分别与玉米秸杆、象草混合青贮，同时添加纤维素复合酶制剂和乳酸菌制剂，研究稻草的最佳青贮模式和五种不同处理稻草混合青贮料对奶牛生产性能的影响，结果表明稻草与玉米秸杆混合青贮（同时添加纤维素复合酶制剂）料对奶牛产奶量显著高于其它青贮组合（P〈0．05），但对乳成分无显著影响（P〉0．05），其它组之间的产奶量和乳成分差异不显著（P〉0．05）。     

基于灰色理论的畜禽粪便环境污染风险预测分析

本文运用灰色建模理论中的灰色数列预测方法,利用北京密云县10个乡镇的畜禽粪便实际负荷量和最大负荷量的确定,对未来年份的畜禽粪便负荷预警值进行预测。结果表明:该流域各乡镇未来十年所受畜禽粪便的污染威胁均呈现逐年加剧趋势,其中石城和番字牌预警值上升最快;冯家峪、大城子和新城子次之,高岭、太师屯和不老屯呈现缓慢上升态势。     

围产前期饲喂DCAD对奶牛营养代谢疾病的影响

试验通过在奶牛围产前期日粮中以?瘙
厫560 g/kg的标准添加阴离子盐,以观察DCAD的饲喂效果.结果表明:在奶牛围产前期饲喂阴离子盐有利于牛体健康,能显著降低产后瘫痪及乳房炎的发病率(P＜0.05),极显著降低胎衣不下和子宫内膜炎的发病率(P＜0.01),同时有利于奶牛产后体况的恢复,缩短奶牛产后第一次发情时间26.5天(P＜0.05),显著提高奶牛产奶量,产后30天奶牛日产奶量可提高11.7%(P＜0.05).